UNITED STATES
DEPARTMENT OF LABOR

Abstract: A three-person utility contractor crew was installing a plastic step, approximately 460 millimeters below street level, in the concrete wall of a manhole. The foreman on the crew removed the 610-millimeter-diameter manhole cover and smelled gasoline. He instructed the other two employees to stand by for 15 minutes to allow the fumes to dissipate. After the wait, one of them descended into the manhole and started to drill a hole with a portable reciprocating hammer connected to a portable generator. He smelled gasoline, and the foreman told the worker to exit the manhole. After waiting several minutes more, the other employee descended into the manhole, positioned his feet on a step about 760 millimeters below street level, rested his back against the top of the manhole, and started drilling. The rotary hammer apparently ignited the gasoline vapors, causing an explosion and starting a fire. The employee in the manhole, who jumped out (Employee #1), sustained third-degree burns to 80 percent of his body. He was hospitalized and died of his injuries 4 days after the accident. The other employee (Employee #2), who had been standing on the street approximately 610 millimeters from the manhole opening, sustained burn injuries to his face, hands, and arms. He was hospitalized.